<xsl:for-each select="project/rows">
            <xsl:sort select="userm"/>
            <!--行合併-->
           
            <tr>
              <td>               
                <xsl:value-of select="userm"/>
              </td>
              <td>
                <xsl:value-of select="ord_no"/>
              </td>
              <td>
                <xsl:value-of select="fact_no1"/>
              </td>
              <td>
                <xsl:value-of select="proj_nm"/>
              </td>
              <td>
                <xsl:value-of select="buil_no"/>
              </td>
              <td>
                <xsl:value-of select="nb_tot"/>
              </td>
            </tr>
          </xsl:for-each>

如何根據<xsl:value-of select="userm"/>來進行行合併，如何寫？哪位知道的告訴下，謝謝！